Balance Pod strength-training tools are similar to the balance half-balls at the gym, but a smart, spiky design adds extra traction. They're great for building core strength and can make simple yoga poses more challenging. ACE certified trainer, Debi Pillarella, MEd, shows us four simple moves.

By Polly Brewster

Before you get started: Beginners should begin with the pods arranged dome side up. To make any move more challenging, flip the pod dome side down. To figure out how long you should hold a pose or do a drill, time yourself once—that's your baseline. In the next set, aim to hold the pose 10 percent longer. (So if your baseline was 20 seconds, try for 22 seconds in the next session.) Try to do three sets with a minute rest in between.

Move 1: Tree Pose

Make this basic yoga pose more challenging by standing on top of a balance pod. Start with your foot positioned just above your ankle. If this placement is too easy, move your foot up to your inner thigh. Once you've mastered this, incorporate your arms: begin with your hands in a prayer position, in front of your chest; if you want to increase the intensity, lift them above your head. Repeat on other side.